This invention relates to an electrical receptacle for an electrical extension cord or an adaptor plug. In particular, this invention relates to a female type receptacle having a power indicator light.
A power indicator light provides a quick, easy visual verification of power delivery to a location remote from a power source. The light saves time and effort when attempting to pinpoint problems in electrical circuits. The power indicator light is particularly useful with an electrical extension cord for use at construction sites or at home on repair projects. The light indicates whether power is delivered through the extension cord to an attached power tool or appliance.
At construction sites, extension cords are often left plugged into the power source for extended periods of time. This leaves the cord exposed to damage caused by weather and various construction equipment. It is not uncommon to plug a power tool, such as a circular saw, into an extension cord and to find that the tool does not work. The user must then determine whether the power tool, extension cord or power source have malfunctioned or simply whether the extension cord is not plugged in. Many of these problems are reduced or eliminated by using an extension cord having a receptacle with a power indicator light. The power indicator light isolates these electrical problems between the attached power tool and the extension cord.
An example of a neon type voltage detector is disclosed by Cook in U.S. Pat. No. 3,234,464. The detector is a thin, detachable device for mounting on the prongs of a male plug. When the plug is inserted into a socket and the prongs contact live contacts within the socket, a neon bulb lights up indicating the presence of electrical power. Unfortunately, the detachable device is very susceptable to breakage and loss.
An example of a power indicator light housed within a female electrical receptacle of an electrical extension cord is disclosed by Grill in U.S. Pat. No. 4,671,597. The indicator light includes a resistor and a lamp connected in series between two terminals of the female receptacle. The lamp is in operation when power is delivered to the terminals through the extension cord. Extended operation, however, can cause the lamp to burn out. Therefore, this type of indicator light is not ideal for use at construction sites where extension cords are left plugged in for extended periods of time.
There is a continuing need for an improved power indicator light for use with an electrical extension cord. A long-life power indicator light that is relatively unsusceptible to breakage or loss is desired.